Comparison : Item # M16-1, Diameter Index Safety System (DISS) 1160A, Medical Air 7/8 Inch (in) Hex Nut
Item # M16-2P, Diameter Index Safety System (DISS) 1160A, Medical Air Handtight Nut with Yellow Collar
Item # M16-2PC, Diameter Index Safety System (DISS) 1160A, Medical Air Handtight Nut with Black and White Collar
Item # M16-8, Diameter Index Safety System (DISS) 1160A, Medical Air Nipple with 1/8 Inch (in) National Pipe Thread (NPT) Male Nipple and Wrench Flats
Item # M16-9, Diameter Index Safety System (DISS) 1160A, Medical Air Nipple with 1/8 Inch (in) National Pipe Thread (NPT) Male Nipple, Wrench Flats, and O-Ring